Problem: Vaccination coverage is well below Healthy People 2010 and 2020 goals, with substantial disparities for low-income and other disadvantaged populations. Health information technology interventions that link communication technologies, like text messaging, with electronic health record data offer low-cost, scalable opportunities to foster vaccination as well as other preventive care behaviors. Studies have demonstrated the effectiveness of such interventions on vaccination coverage at levels in line with other forms of reminder/recall particularly in low-income populations for whom other forms of reminder-recall have not been successful. However, their effect has not been as robust as needed. More effective messaging interventions are needed. Adolescents, in particular minority adolescents, are not adequately protected against human papillomavirus (HPV) and its potential sequelae, which include cancer and genital warts. Despite the highly efficacious vaccine being recommended for all adolescents, completion rates among those who initiate the 3- dose series are low, particularly among minorities. Using a non-randomized design, we demonstrated the effect of conventional text message vaccine reminders, notifying a parent their child was due for the next dose, in increasing HPV vaccination in primarily, urban Latina adolescents. Although much improved over controls, only 50% received their next dose on time and only 45% completed the series. While these results strongly support the potential effectiveness of this intervention in minority populations for whom traditional forms of vaccination reminders have not worked, still fewer than half completed the vaccine series. A potential advantage of text message HIT interventions that has not been well investigated is the ability to provide personalized messages. We propose to compare the use of personalized HPV vaccine text message reminders to conventional text message reminders among minority adolescents in a pragmatic randomized trial. The trans-theoretical model of behavior change will guide the tailoring of our text messages. Specific Aim: To compare the effectiveness in improving HPV vaccine series completion for minority adolescents of personalized text message reminders with tailored vaccine-health-literacy-promoting information vs. conventional text message vaccination reminders. Methods: 956 parents of adolescent girls and boys who have received the 1st HPV vaccine dose will be randomized to receive either: 1) personalized or (2) conventional text messages. Personalized reminders include vaccine health literacy-promoting information tailored to parental stage of decision-making. Conventional text message reminders solely notify a parent their child is due for the next dose such as used in previous HPV vaccine text message studies. Outcomes: The primary outcome is completion of 3-dose HPV vaccine series within 12 months. If successful this project could support a new paradigm in interactive health communication in a low cost, scalable manner that may be readily disseminated.